/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


//
// Log4j uses the JUnit framework for internal unit testing. JUnit
// available from
//
//     http://www.junit.org
package org.apache.log4j.helpers;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.helpers.CyclicBuffer;
import org.apache.log4j.spi.LoggingEvent;


/**
   Unit test the {@link CyclicBuffer}.

   @author Ceki G&uuml;lc&uuml;

*/
public class CyclicBufferTestCase extends TestCase {
  static Logger logger = Logger.getLogger("x");
  static int MAX = 1000;
  static LoggingEvent[] e = new LoggingEvent[MAX];

  {
    for (int i = 0; i < MAX; i++) {
      e[i] = new LoggingEvent("", logger, Level.DEBUG, "e" + i, null);
    }
  }

  public CyclicBufferTestCase(String name) {
    super(name);
  }

  public void setUp() {
  }

  public void test0() {
    int size = 2;

    CyclicBuffer cb = new CyclicBuffer(size);
    assertEquals(cb.getMaxSize(), size);

    cb.add(e[0]);
    assertEquals(cb.length(), 1);
    assertEquals(cb.get(), e[0]);
    assertEquals(cb.length(), 0);
    assertNull(cb.get());
    assertEquals(cb.length(), 0);

    cb = new CyclicBuffer(size);
    cb.add(e[0]);
    cb.add(e[1]);
    assertEquals(cb.length(), 2);
    assertEquals(cb.get(), e[0]);
    assertEquals(cb.length(), 1);
    assertEquals(cb.get(), e[1]);
    assertEquals(cb.length(), 0);
    assertNull(cb.get());
    assertEquals(cb.length(), 0);
  }

  /**
     Test a buffer of size 1,2,4,8,..,128
   */
  public void test1() {
    for (int bufSize = 1; bufSize <= 128; bufSize *= 2)
      doTest1(bufSize);
  }

  void doTest1(int size) {
    //System.out.println("Doing test with size = "+size);
    CyclicBuffer cb = new CyclicBuffer(size);

    assertEquals(cb.getMaxSize(), size);

    for (int i = -(size + 10); i < (size + 10); i++) {
      assertNull(cb.get(i));
    }

    for (int i = 0; i < MAX; i++) {
      cb.add(e[i]);

      int limit = (i < (size - 1)) ? i : (size - 1);

      //System.out.println("\nLimit is " + limit + ", i="+i);
      for (int j = limit; j >= 0; j--) {
        //System.out.println("i= "+i+", j="+j);
        assertEquals(cb.get(j), e[i - (limit - j)]);
      }

      assertNull(cb.get(-1));
      assertNull(cb.get(limit + 1));
    }
  }

  public void testResize() {
    for (int isize = 1; isize <= 128; isize *= 2) {
      doTestResize(isize, (isize / 2) + 1, (isize / 2) + 1);
      doTestResize(isize, (isize / 2) + 1, isize + 10);
      doTestResize(isize, isize + 10, (isize / 2) + 1);
      doTestResize(isize, isize + 10, isize + 10);
    }
  }

  void doTestResize(int initialSize, int numberOfAdds, int newSize) {
    //System.out.println("initialSize = "+initialSize+", numberOfAdds="
    //	       +numberOfAdds+", newSize="+newSize);
    CyclicBuffer cb = new CyclicBuffer(initialSize);

    for (int i = 0; i < numberOfAdds; i++) {
      cb.add(e[i]);
    }

    cb.resize(newSize);

    int offset = numberOfAdds - initialSize;

    if (offset < 0) {
      offset = 0;
    }

    int len = (newSize < numberOfAdds) ? newSize : numberOfAdds;
    len = (len < initialSize) ? len : initialSize;

    //System.out.println("Len = "+len+", offset="+offset);
    for (int j = 0; j < len; j++) {
      assertEquals(cb.get(j), e[offset + j]);
    }
  }

  public static Test suite() {
    TestSuite suite = new TestSuite();
    suite.addTest(new CyclicBufferTestCase("test0"));
    suite.addTest(new CyclicBufferTestCase("test1"));
    suite.addTest(new CyclicBufferTestCase("testResize"));

    return suite;
  }
}
